Well, it's not the prettiest thing I've ever seen, that's for sure. Looks like the mutant offspring of a Walther PDP and a Kel-Tec P17 with the grip safety of a Springfield XDS and the magazine release of a Sig P365. The extended magazine baseplate, I'm assuming, is probably for the 15-round setup and, if so, I'm assuming there's a 10- or 12-round flush-fitting magazine, which would reduce the grip length and put it more in line with something like a Sig P365XL, which is a fairly small pistol. (Definitely smaller than a Glock 19, anyway.) With the extended baseplate shown, it's probably got the same dimensions as a Glock 48, which is the same length/height as a G19 but is as thin as a G43. I'm betting this was Kel-Tec's strategy here: "Lookie, folks! With the G48, you have to buy aftermarket magazines and swap the magazine release button in order to get 15 rounds in a gun that size, but ours comes with 15-rounders from the factory! Wheeeee!" (And hopefully its MSRP is less than the G48, so at least they might also have that going for them.)
Essentially, it seems pretty much aimed to compete with the G48 and P365XL. I won't go so far as to say it's useless, unwanted, or whatever else, but ... yeah. Kinda underwhelming. And as Kirk indicated, there is NO WAY that this "replaces" the P3AT in any way, shape, or form. Good luck trying to cram a G48 or P365XL sized pistol in a pocket as easily as a P3AT...
I dunno what the heck is going on with the back of the slide there. Almost looks like a .22 LR blowback setup, like the P17, unless it's just a polymer cover for an optics mount or something ... which is a really bizarre way of doing things, if that's the case. Being that it goes up to the back of the ejection port and stops is what makes me think it could be an optics mount, but again, it's weird that the piece goes all the way down and all the way to the back of the slide. Really weird. Maybe it has something to do with how the thing field-strips, which also would be a really bizarre way of doing things...
Even from a photo, I can already tell the grip texture on the sides of the grip are stupid-excessive in aggressiveness - basically, little squares of M&P 2.0 style 60-grit sandpaper. Ugh. When are gun manufacturers going to learn that putting aggressive texture ON THE SIDES of the grip DOES NOT HELP because that's not where the majority of the shooter's grip force is applied with their hands? The front and back straps should get that sort of texture, a-la the Wilson Combat grip modules for the Sig P320. Putting it on the sides of the grip just makes it a cheese grater on skin and clothing. Easily fixable with a bit of sandpaper to dull the texture, but stupid that manufacturers keep doing this.
At least it FINALLY looks like Kel-Tec decided to start making the slide stop out of a machined part instead of a cheap, flimsy stamped-steel piece like they did with the P11 and PF9.
Anyway. Guess we'll all hafta wait for SHOT Show for more. It's sorta interesting, but also fairly disappointing.